STS-92 Day 7 Highlights

Mission Specialists Leroy Chiao and Bill McArthur will team up once
again today to conduct the third scheduled space walk of this mission,
setting the stage for future on-orbit construction and the arrival of
the Expedition 1 crew in November.

Today^Òs space walk, scheduled to begin just before 9:30 a.m.,
paves the way for installation of the station^Òs large solar arrays
later this year as Chiao and McArthur install two current converter
units to process power that will be generated by the arrays, and
prepare the worksite where the arrays will be attached. The converter
units ^Ö called DDCUs ^Ö are 129-pound power processing systems
that will provide precisely regulated power output from the massive
solar arrays. With assistance from robot arm operator Koichi Wakata
who will ferry the spacewalkers around the growing station, Chiao and
McArthur will unfasten the DDCUs from their locations in
Discovery^Òs payload bay and install them on the Z1 truss in a
process that will take about two hours to complete.

They will then turn their attention to final power cable connections
on both the Z1 truss and newly-installed docking port, PMA-3,
connecting and reconfiguring cables to route power from PMA-2 to PMA-3
for the arrival of Endeavour and STS-97 crew next month. Finally,
McArthur and Chiao will attach a second tool storage box on the Z1
truss, providing a place to hold the tools and spacewalking aids that
will be used during upcoming assembly flights. McArthur will retrieve
a bag of tools and hardware attached to the exterior of the Unity
module and place it in the storage boxes. The tools were temporarily
stowed on Unity during a May 1999 space walk conducted by astronauts
Tammy Jernigan and Dan Barry during STS-96, the first Shuttle docking
with the International Space Station.

Overnight, space station flight controllers in Houston completed
commanding a series of 16 bolts to their closed position, securing
PMA-3 to its new location on the Unity module, following a planned
12-hour thermal conditioning period. The docking port, installed
during yesterday^Òs space walk, will be used by the STS-97 crew
when Endeavour docks with the International Space Station.

Mission Specialists Leroy Chiao and Bill McArthur completed the
third successful spacewalk of Discovery'sSTS-92 mission at 4:18
p.m. CDT Tuesday, installing two DC-to-DC converter units atop the
International Space Station's new Z1 Truss. Those two 129-pound
converters, called DDCUs, will convert electricity generated by the
huge solar arrays to be attached during the next shuttle mission to
the proper voltage.

Today's spacewalk began at 9:30 a.m. and ended at 4:18 p.m., almost
exactly as planned. Total time of Tuesday's EVA was 6 hours, 48
minutes. That brings to 20 hours, 23 minutes the total time of the
three spacewalks performed thus far in Discovery's mission, and the
total time of space station construction spacewalks to 62 hours, 38
minutes. A fourth spacewalk is scheduled for Wednesday. It too will
prepare the Z1 Truss for attachment of the solar arrays.

Chaio and McArthur were helped by the robot arm in moving around the
station. Koichi Wakata and Mike Lopez-Alegria split the arm-operation
duties on Tuesday, with Lopez-Alegria taking the first half.

The spacewalkers also completed power cable connections on both the
Z1 truss and newly installed docking port, PMA-3. They connected and
reconfigured cables to route power from Pressurized Mating Adapter-2
to PMA-3 for the arrival of Endeavour and the STS-97 crew next
month. They also attached a second tool storage box on the Z1 truss,
providing a place to hold the tools and spacewalking aids for future
assembly flights. McArthur stocked the boxes with tools and hardware
that had been attached to the Unity module. STS-96 Astronauts Tammy
Jernigan and Dan Barry had left the tools on the outside of Unity
during a May 1999 spacewalk.

After today's spacewalk, Discovery Commander Brian Duffy and Pilot
Pam Melroy completed the second of the three station reboosts
scheduled for STS-92. They fired reaction control system jets in a
series of pulses of 1.4 seconds each, over a 30-minute period, gently
raising the station's orbit by about 1.7 statute miles.

On Wednesday astronauts Jeff Wisoff and Lopez-Alegria are scheduled
to perform the fourth and final spacewalk of the STS-92 flight. Among
activities will be deployment of the Z1 utility tray, and opening and
closing of the Z1 Manual Berthing Mechanism latches. Wisoff and
Lopez-Alegria also will test the SAFER, or "simplified aid for EVA
rescue," a backpack that could enable an astronaut drifting away from
the shuttle or the station to get back to the spacecraft. Finally,
they will test methods for rescuing an incapacitated astronaut.